Added volume adjust sound behind the flag.

media/audio/sounds/wav_audio_handler.cc

-// Copyright 2013 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-#include "media/audio/sounds/wav_audio_handler.h"
-
-#include <algorithm>
-#include <cstring>
-
-#include "base/logging.h"
-#include "base/sys_byteorder.h"
-#include "media/base/audio_bus.h"
-
-namespace {
-
-const char kChunkId[] = "RIFF";
-const char kFormat[] = "WAVE";
-const char kSubchunk1Id[] = "fmt ";
-const char kSubchunk2Id[] = "data";
-
-// The size of the header of a wav file. The header consists of 'RIFF', 4 bytes
-// of total data length, and 'WAVE'.
-const size_t kWavFileHeaderSize = 12;
-
-// The size of a chunk header in wav file format. A chunk header consists of a
-// tag ('fmt ' or 'data') and 4 bytes of chunk length.
-const size_t kChunkHeaderSize = 8;
-
-// The minimum size of 'fmt' chunk.
-const size_t kFmtChunkMinimumSize = 16;
-
-// The offsets of 'fmt' fields.
-const size_t kAudioFormatOffset = 0;
-const size_t kChannelOffset = 2;
-const size_t kSampleRateOffset = 4;
-const size_t kByteRateOffset = 8;
-const size_t kBitsPerSampleOffset = 14;
-
-// Some constants for audio format.
-const int kAudioFormatPCM = 1;
-
-// Reads an integer from |data| with |offset|.
-template<typename T> T ReadInt(const base::StringPiece& data, size_t offset) {
-  CHECK_LE(offset + sizeof(T), data.size());
-  T result;
-  memcpy(&result, data.data() + offset, sizeof(T));
-#if !defined(ARCH_CPU_LITTLE_ENDIAN)
-  result = base::ByteSwap(result);
-#endif
-  return result;
-}
-
-}  // namespace
-
-namespace media {
-
-WavAudioHandler::WavAudioHandler(const base::StringPiece& wav_data)
-    : num_channels_(0),
-      sample_rate_(0),
-      byte_rate_(0),
-      bits_per_sample_(0) {
-  CHECK_LE(kWavFileHeaderSize, wav_data.size()) << "wav data is too small";
-  CHECK(wav_data.starts_with(kChunkId) &&
-        memcmp(wav_data.data() + 8, kFormat, 4) == 0)
-      << "incorrect wav header";
-
-  uint32 total_length = std::min(ReadInt<uint32>(wav_data, 4),
-                                 static_cast<uint32>(wav_data.size()));
-  uint32 offset = kWavFileHeaderSize;
-  while (offset < total_length) {
-    const int length = ParseSubChunk(wav_data.substr(offset));
-    CHECK_LE(0, length) << "can't parse wav sub-chunk";
-    offset += length;
-  }
-}
-
-WavAudioHandler::~WavAudioHandler() {
-}
-
-bool WavAudioHandler::AtEnd(size_t cursor) const {
-  return data_.size() <= cursor;
-}
-
-bool WavAudioHandler::CopyTo(AudioBus* bus,
-                             size_t cursor,
-                             size_t* bytes_written) const {
-  if (!bus)
-    return false;
-  if (bus->channels() != num_channels_) {
-    LOG(ERROR) << "Number of channel mismatch.";
-    return false;
-  }
-  if (AtEnd(cursor)) {
-    bus->Zero();
-    return true;
-  }
-  const int remaining_frames = (data_.size() - cursor) / bytes_per_frame_;
-  const int frames = std::min(bus->frames(), remaining_frames);
-  bus->FromInterleaved(data_.data() + cursor, frames, bytes_per_sample_);
-  *bytes_written = frames * bytes_per_frame_;
-  bus->ZeroFramesPartial(frames, bus->frames() - frames);
-  return true;
-}
-
-int WavAudioHandler::ParseSubChunk(const base::StringPiece& data) {
-  if (data.size() < kChunkHeaderSize)
-    return data.size();
-  uint32 chunk_length = ReadInt<uint32>(data, 4);
-  if (data.starts_with(kSubchunk1Id)) {
-    if (!ParseFmtChunk(data.substr(kChunkHeaderSize, chunk_length)))
-      return -1;
-  } else if (data.starts_with(kSubchunk2Id)) {
-    if (!ParseDataChunk(data.substr(kChunkHeaderSize, chunk_length)))
-      return -1;
-  } else {
-    LOG(ERROR) << "Unknown data chunk: " << data.substr(0, 4) << ".";
-  }
-  return chunk_length + kChunkHeaderSize;
-}
-
-bool WavAudioHandler::ParseFmtChunk(const base::StringPiece& data) {
-  if (data.size() < kFmtChunkMinimumSize) {
-    LOG(ERROR) << "Data size " << data.size() << " is too short.";
-    return false;
-  }
-  DCHECK_EQ(ReadInt<uint16>(data, kAudioFormatOffset), kAudioFormatPCM);
-  num_channels_ = ReadInt<uint16>(data, kChannelOffset);
-  sample_rate_ = ReadInt<uint32>(data, kSampleRateOffset);
-  byte_rate_ = ReadInt<uint32>(data, kByteRateOffset);
-  bits_per_sample_ = ReadInt<uint16>(data, kBitsPerSampleOffset);
-  bytes_per_sample_ = bits_per_sample_ >> 3;
-  bytes_per_frame_ = num_channels_ * bytes_per_sample_;
-  return true;
-}
-
-bool WavAudioHandler::ParseDataChunk(const base::StringPiece& data) {
-  data_ = data;
-  return true;
-}
-
-}  // namespace media